Method for drying and cooling meal and apparatus for the working thereof

ABSTRACT

There is described a method for drying and cooling meal which comprises bringing the damp and hot meal temporarily inside an enclosure the inner pressure of which is maintained substantially below the atmospheric pressure.

United States Patent De Smet Nov. 11, 1975 [54] METHOD FOR DRYING AND COOLING 1,920,107 7/1933 Richardson 34/15 X M L AND APPARATUS FOR THE 2,166.351 7/1939 Hagen 34/92 X 2.448.272 8/1948 Payne et al. 34/15 WORKING THEREOF 3.099,138 7/1963 Hightower et a1. 34/15 [75] inventor: Jean Albert De Smet, Wilrijk, 3.293.766 12/1966 Togashi et a1. 34/92 Belgium 3,633,283 l/l972 Mishkin et al. 34/73 [73] Assignee: Extraction de Smet, Edegem,

v Belglum Primary E.\'aminerJ0hn J. Camby [22] Filed; May 14, 1974 Attorney, Agent, or FirmWenderoth, Lind & Ponack [21] Appl. No.: 469,882

[30] Foreign Application Priority Data [57] ABSTRACT May 15, 1973 Belgium 799459 There is described a method for drying and Cooling meal which comprises bringing the damp and hot meal [22] :18315 34/15, 34/92 temporarily inside an enclosure the inner pressure of Flt. .f is maintained substantially below the atm0 leld o arc 34/15, 92 Spheric pressure [56] References Cited UNITED STATES PATENTS 4 Claims, 4 Drawing Figures 888.257 5/1908 Passburg 34/92 US. Patent Nov. 11,1975 Sheet10f2 3,918,169

US. Patent Nov. 11, 1975 Sheet 2 of2 3,918,169

F/& 2

BACKGROUND OF THE INVENTION This invention pertains to a method and apparatus for drying and cooling meal.

The cakes which have been treated inside a solventoperated extractor comprise at the outlet from the extracting apparatus, a substantial proportion of solvent which can amount to from 50 to 150% of the weight of the dry meal.

The solvent is removed from such cakes by a livestream treatment in a so-called toaster apparatus. The output material from such apparatus is free from solvent but it has a humidity in the range of 20% by weight. The material temperature lies in the range of Such material which is thus comprised of damp meal, and has to be dried and cooled. Up to now the material has been subjected to two succeeding operations, namely a first drying operation and a second cooling operation.

SUMMARY OF THE INVENTION An object of the present invention is to combine both such operations into a single operation and to perform in a relatively short time the drying and cooling.

For this purpose, the damp and hot meal is brought temporarily inside an enclosure the inner pressure of which is maintained substantially below the atmospheric pressure.

In an advantageous embodiment of the invention, the meal is temporarily introduced inside an enclosure wherein the pressure is maintained in the range of 40 torr.

The invention further relates to an apparatus for drying and cooling meal according to the above-defined method.

The apparatus according to the inventioncomprises an air-tight container with an inlet opening at the top thereof and an outlet opening at the bottom thereof, as well as a sealing closure for the inlet opening, a sealing closure for the outlet opening and means connected to a third container opening forming a gas suction opening.

In a particular embodiment of the invention, the apparatus comprises a shaft arranged inside the container, at least one scraper mounted on the shaft adjacent the container bottom and driving means for the shaft.

In a preferred embodiment of the invention, at least one of the closures comprises two valves and an intermediate lock-chamber.

In a very advantageous embodiment, at least one of the closures is a rotating gate.

BRIEF DESCRIPTION OF THE DRAWINGS Other details and features of the invention will be apparent from the description given below by way of a non-limiting example and with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic showing of an apparatus for drying and cooling meal according to the invention.

FIG. 2 is a front view partly in section and on a larger scale of part of the apparatus shown in FIG. 1.

FIG. 3 is a plan view on the same scale as FIG. 2, of that apparatus part shown in FIG. 2.

FIG; 4 is a cross-section through another embodiment of a member of that apparatus part shown in FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION In the various figures, the same reference numerals are used to illustrate to similar elements.

In a device for extracting oil and fatty materials from oil-bearing seeds, the apparatus according to the invention follows a toaster, the lowermost part of which shown diagrammatically in FIG. 1, is indicated by reference numeral 1. The toaster is preceded by the extractor.

The oil-bearing seeds, usually first crushed, are fed to the extractor inlet and leave the same as solventimpregnated cakes. The cake-like meal from the extractor contains approximately 50 to 150 by weight of solvent relative to the dry meal.

Inside the toaster which is an already-known apparatus, the meal which is still impregnated with extracting solvent at the apparatus inlet, is separated from the solvent, notably by injecting live steam. The meal produced at the toaster outlet has a moisture content of 19 to 20% by weight for a temperature in the range of C. This moist meal is fed to the apparatus shown diagrammatically in FIG. 1, and part of such apparatus is shown with further details in FIGS. 2 and 3.

The lowermost part 1 of the toaster ends in an outlet ring 2. Between a flange 3 of this outlet ring and a top flange 4 of a lock formed by a pipe 5, is mounted an hydraulically-controlled valve 6.

The valve 6 and valves 11,20 and 27 described hereinbelow, are of a known type and will consequently not be further described.

As shown diagrammatically for valve 6, such a valve comprises notably a ring 52 having on the inner side thereof a groove 54 wherein fits the edge of a slide 53 when such slide lies in the completely-closed position as shown in FIG. '2.

Slide 53 can be retracted along the direction of arrow 56 to free the passage. The slide 53 then moves through a slot 55. Outside the ring along the side of slot 55, the slide 53 is provided with hydraulic driving means.

Between the lower flange 7 of the lock 5 and an upper flange 8 of the container inlet ring 9 which bounds an enclosure 10 and is further described hereinbelow, is mounted a second hydraulically-controlled valve 11.

The container bounding the enclosure 10 is formed by a ring 12, a flat bottom 13 and a flat cover 14.

Along the outer side the bottom 13 and the cover 14 are reinforced by laths 15 which form together a grating. Laths 15 are integral with hoops 16 which lie in extension of ring 12 above cover 14 and below bottom 13. The cover 14 has an opening 17 where the inlet ring 9 connects with cover 14.

A corresponding opening 18 is provided in the container bottom where an outlet ring 19 connects to bottom 13.

A hydraulically-controlled valve 20 is mounted between flange 21 of the container outlet ring 19 and the top flange 22 of pipe 23 which forms a lock.

Between the lowermost flange 24 of pipe 23 which forms a lock and flange 25 of the end discharge pipe 26 of the apparatus is mounted a hydraulically-controlled valve 27.

The container bears on four supporting feet 28 that bear against ring 12 and bottom 13. Where the supporting feet 28 engage container bottom 13, the hoop 16 extending downwards ring 12, is cut out. On two small beams 29 made fast to the cover 14 into notches cut out in laths 15, is mounted a gear-box 30 to which is connected a motor 31. A pulley 32 mounted on shaft 33 of motor 31 drives through a belt 34 a pulley 35 mounted on the input shaft 34 of gear-box 30.

The output shaft 37 of gear-box 30 bears a gear wheel 38 which drives a gear wheel 39 mounted on the top portion of shaft 40. Shaft 40 is co-axial with ring 12, and extends through the entire height of the container. Shaft 40 extends through the cover 14 and is mounted in a lower bearing 41 made fast to container bottom 13 and in a top bearing 42 made fast to container cover 14.

Scrapers 43 are mounted on shaft 40 inside the container adjacent the bottom 13 thereof.

In the cover 14 is also provided an opening 44 which is surrounded by a rim 45 with a flange 46 to which is conducted a duct 47 leading to a suction device 48. The gases removed by device 48 are lead through pipe 49 to condenser 50 from which the condensate moisture, that is the water, is discharged to the outlet 51.

It is to be noticed that the enclosure is bounded both along the supply side, that is the toaster side and along the discharge side, that is the side of end discharge pipe 26, by sealed closure means for the inlet and outlet openings. Such sealed closure means are formed by the unit comprised of valves 6 and 11 at the inlet and of valves and 27 at the outlet.

The moist meal which is fed to the outlet ring when leaving the toaster, is retained by valve 6. Valve 6 is opened at regular time intervals, while valve 11 is retained closed. The moist meal from the toaster is thus brought in the lock formed by pipe 5. After completely or partly filling this lock, valve 6 is closed and valve 11 is then opened, in such a way that the meal collected inside the lock falls in the enclosure 10.

Such lock that lies between two valves which are never opened at the same time, thus forming a gate allows feeding the moist meal from the toaster inside the enclosure 10 without the pressure inside the enclosure having to be balanced with the higher pressure inside the toaster.

The motor 31 drives shaft 40 through the pulleys, belt, gear-box and gear wheels. The scrapers 43 mounted on shaft 40 that lie adjacent container bottom 13, thus move along bottom 13. Scrapers 43 distribute more or less regularly the meal over the enclosure bottom and also drive the meal towards outlet ring 19. When valve 20 is closed, the meal cannot leave the enclosure. However the valve 20 is opened at given time intervals while valve 27 is retained closed, in such a way that the metal is brought inside the lock formed by pipe 23. When the lock is completely or partly filled with meal, the valve 20 is then closed and valve 27 is opened, in such a way that the meal is discharged from the apparatus through the discharge pipe 26. Valves 20 and 27 and pipe 23 thus form a gate.

As the meal stays inside enclosure 10, it looses a substantial portion of the moisture thereof.

The suction device 48 evacuates the gases, that is air and vapours from enclosure 10, through duct 47. There thus appears a negative pressure inside enclosure 10 and such negative pressure is retained therein. Such pressure inside enclosure 10 is for instance in the range of 40 torr, that is substantially lower than atmospheric pressure. As the moist meal from the toaster has a temperature in the range of C, a substantial proportion of the moisture contained in the meal is vaporized by the lower pressure inside the enclosure. As the vaporizing is an endothermic transformation, the meal is cooled down as it looses part of the moisture thereof. The drying of the meal is thus automatically combined with the of the meal.

The meal brought to the enclosure outlet and therefrom to the end discharge pipe 26, has for instance a moisture content of 10% by weight relative to dry meal and it has for instance a temperature in the range of 28 to 30C which is an ideal temperature for bagging and storing into silos.

The vapours removed by the suction device 48 are condensed in condensor 50.

In another embodiment of the above-described device, the two-valve locks are replaced by rotating gates.

The lock 5 bounded by valves 6 and 11 is replaced by a rotating gate and the lock 23 bounded by valves 20 and 27 is replaced by another rotating gate.

Such a rotating gate is shown diagrammatically in FIG. 4.

The horizontal-axis cylinder 57 replaces the pipe 5 or 23 forming a vertical-axis lock. In the top wall portion of cylinder 57 is provided a circular opening 58 surrounded by an inlet ring 59 the flange 60 of which is connected to flange 3 of the toaster outlet ring 2 or to flange 21 of the outlet ring 19 of that container bounding the enclosure 10.

In the lower wall portion of cylinder 57 is provided a circular opening 61 which is surrounded by an outlet ring 62 the flange 63 of which is connected to flange 8 of the inlet ring 9 of that container bounding the enclosure 10 or to flange 25 of the device end discharge pipe 26.

Along the cylinder axis is located a shaft 64 on which is made fast by means of a key 65, a rotor 66 with four arms 67. The shaft 64 and consequently the rotor 66 are rotated in the direction shown by arrow 68. There is never a direct free passageway from the inlet ring 59 to the outlet ring 62 of the rotating gate, as at least two arms 67 of rotor 66 close such passageway.

The pressure differential between the toaster, the enclosure 10 and the end discharge pipe 26 is thus retained; the feeding and discharge of the meal in enclosure 10 are performed by arms 67 of rotor 66.

As such rotating gates are known per se, no further description is deemed necessary.

It must be understood that the invention is in no way limited to the above embodiments and that many changes can be made therein without departing from the scope of the invention as defined by the appended claims.

For instance, the pressure valve of 40 torr inside the apparatus is not critical and a value in the range of 30 torr is sufficient in every aspect.

If a batch operation of the apparatus can be considered, the locks or gates are not required, and a simple stop valve at the inlet and outlet of the enclosure becomes sufficient. However in such a case, the underpressure has to be restored in the enclosure after each filling thereof.

I claim:

1. An installation for the treatment of meal cakes discharged from a solvent-operated extractor, said installation comprising:

an air tight container having a suction opening therein;

suction means connected to said suction opening by a duct for maintaining a predetermined reduced pressure in said container;

a condenser connected to said suction means and having a discharge outlet;

meal toasting means connectable to an extractor for toasting meal cakes received therefrom, said toasting means having a discharge;

first gate means connecting said toasting means discharge with said container for supplying moist meal from said extractor to said container while maintaining said predetermined reduced pressure in said container;

a shaft rotatably mounted to extend vertically through said container, said shaft having attached thereto scraper means for regularly distributing said meal in said container, said meal being cooled and dried in said container;

said container having therein a discharge outlet; and

second gate means connected to said container discharge outlet for discharging cooled and dried meal from said container to said container discharge outlet while maintaining said predetermined reduced pressure in said container;

2. An installation as claimed in claim 1, wherein said suction means comprises means for maintaining a pressure of 40 Torr in said container.

3. A method for treating solvent-impregnated meal cakes discharged from a solvent-operated extractor, said method comprising:

depositing solvent-impregnated meal cakes from an extractor into a meal toasting device, and injecting live steam into said meal within said toasting device;

providing an air tight container;

maintaining a predetermined reduced pressure within said container;

selectively passing said steam injected meal from said toasting device through a first gate device into said container while maintaining said predetermined reduced pressure in said container;

operating a scraper device within said container to regularly distribute said meal within said container, while maintaining said predetermined reduced pressure in said container and drying and cooling Torr in said container. 

1. An installation for the treatment of meal cakes discharged from a solvent-operated extractor, said installation comprising: an air tight container having a suction opening therein; suction means connected to said suction opening by a duct for maintaining a predetermined reduced pressure in said container; a condenser connected to said suction means and having a discharge outlet; meal toasting means connectable to an extractor for toasting meal cakes received therefrom, said toasting means having a discharge; first gate means connecting said toasting means discharge with said container for supplying moist meal from said extractor to said container while maintaining said predetermined reduced pressure in said container; a shaft rotatably mounted to extend vertically through said container, said shaft having attached thereto scraper means for regularly distributing said meal in said container, said meal being cooled and dried in said container; said container having therein a discharge outlet; and second gate means connected to said container discharge outlet for discharging cooled and dried meal from said container to said container discharge outlet while maintaining said predetermined reduced pressure in said container.
 2. An installation as claimed in claim 1, wherein said suction means comprises means for maintaining a pressure of 40 Torr in said container.
 3. A method for treating solvent-impregnated meal cakes discharged from a solvent-operated extractor, said method comprising: depositing solvent-impregnated meal cakes from an extractor into a meal toasting device, and injecting live steam into said meal within said toasting device; providing an air tight container; maintaining a predetermined reduced pressure within said container; selectively passing said steam injected meal from said toasting device through a first gate device into said container while maintaining said predetermined reduced pressure in said container; operating a scraper device within said container to regularly distribute said meal within said container, while maintaining said predetermined reduced pressure in said container and drying and cooling said meal in said container; and selectively passing the thus dried and cooled meal from said containEr through a second gate device while maintaining said predetermined pressure in said container.
 4. A method as claimed in claim 3, wherein said step of maintaining comprises maintaining a pressure of 40 Torr in said container. 